Communications: electrical – Selective – Intelligence comparison for controlling
Reexamination Certificate
2000-01-14
2003-03-25
Horabik, Michael (Department: 2735)
Communications: electrical
Selective
Intelligence comparison for controlling
C455S562100
Reexamination Certificate
active
06538560
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The invention relates to the field of keyless access control devices. In particular, the invention relates to a keyless device for controlling access to motor vehicles having a transceiver device, which is allocated to the motor vehicle, and a mobile transponder, which transceiver device comprises a plurality of transmitters (low-frequency transmitters), which operate in the inductive frequency range and are allocated to different sides of the motor vehicle, for the purpose of transmitting a low-frequency code signal (LF signal), and a receiver unit, which operates in the high-frequency range (HF-range), for the purpose of receiving HF-response signals from the transponder, and which transponder comprises a receiver for the purpose of receiving the LF-signal and comprises an HF-transmitter for the purpose of transmitting an HF-response signal upon receiving the LF-signal.
2. Background Art
Furthermore, the invention relates to a keyless method for checking access authorization in motor vehicles.
This type of device and method have been disclosed in the papers “Ein Fahrzeugsicherungssystem ohne mechanischen Schlüssel” [a motor vehicle security system without a mechanical key] by Ch. Schneider and U. Schrey, published in: “Automobiltechnische Zeitschrift 96” [automotive magazine 96] (1994) no. 5 and “Smart-Card—Abschied vom Autoschlüssel” [The smart-card—The end of the car key] by U. Schrey, Ch. Schneider and M. Siedentrop, published in: “Siemens-Zeitschrift 1/96” [Siemens-Magazine 1/96]. The access control device described in these documents consists substantially of a transceiver device, which is allocated to the motor vehicle, and of a mobile transponder. The transceiver device comprises three transmitters (LF-transmitters) which operate in the inductive frequency range and of which one transmitter is allocated to the vehicle door, another is allocated to the passenger door and the third transmitter is allocated to the rear of the vehicle respectively. The transmitting antennae of the LF-transmitters are integrated into the respective side doors or into the rear bumper. Each LF-transmitter is connected to the door handle, allocated to the respective door, or to the boot button in such a manner that upon actuation thereof, the LF-transmitter which is allocated to this region of the vehicle transmits a low-frequency code signal (LF-signal). In contrast, the remaining LF-transmitters remain inactive and do not transmit any LF-signals.
The transceiver device which is allocated to the motor vehicle is also equipped with an HF-receiver for the purpose of receiving an HF-signal from the transponder. The transponder response signal received in the HF-receiver influences a control device which is equipped with a processor and in which the received response signal, which has been received as a crypto-code, is decrypted and checked for validity. If a match is established, a corresponding control signal is transmitted to the respective door locking mechanism for the purpose of unlocking the particular door, of which the door handle has been actuated beforehand.
The transponder is provided in the form of a so-called access card having an LF-receiver and a low-power HF-transmitter. The inductive receiving antenna is designed as a frame antenna and the high-frequency transmitting antenna is designed as a printed circuit board antenna. The LF-signal received by the LF-receiver of the transponder is decoded in the transponder. A microprocessor which is allocated to the transponder then calculates the codeword, which is contained in the LF-signal, using a security algorithm and transmits the result by means of the HF-transmitting unit to the HF-receiver of the transceiver device allocated to the motor vehicle.
Transmitting LF-signals for the purpose of “waking-up” the transponder serves to predetermine a functional radius limitation by virtue of the rapidly diminishing magnetic field. It is only possible to receive the transmitted LF-signal within one functional radius of 1.5 to 2 meters. This ensures that only those transponders which are actually located in this near-field region are woken up by the actuated LF-transmitter. The required actuation of a door handle or a boot button and the limitation of the functional radius serve to localize in a defined manner the transponder or the person carrying the transponder.
In order to render it possible to unlock the respective motor vehicle door as quickly as possible, modified door handle and lock mechanisms are used which render it possible for the door, on which the handle has been pulled, to open immediately. Even the provision of these type of mechanisms does not make it possible to shorten the period of time which the [sic] requires for the purpose of transmitting the data transmitted from the LF-transmitter to the transponder. This applies in particular if complicated crypto-codes are to be transmitted on this low-frequency path, since this type of approach requires a specific period of time owing to the low data transmission speed. However, the transmission of the decoded response signal of the transponder to the HF-receiver only slightly delays the beginning of the door release action.
A further keyless device for controlling access to vehicles is disclosed in DE 43 29 697 C2. This device utilizes a central LF-transmitter for the purpose of transmitting the low-frequency code signal. However, in the case of this device it is provided that the LF-transmitter transmits LF-signals cyclically in specific time intervals. Only when the transponder, which is allocated to the motor vehicle, is located in the functional radius of the LF-transmitter, is it woken up and transmits its response signal back. In order to trigger the release mechanism, it is not necessary in the case of this device to have to actuate a door handle or a boot button. Since it is not possible in the case of this device to localize the transponder for the purpose of unlocking merely specific doors, this access control device is only suitable for motor vehicles which have central locking. In the case of this previously known access control device the release action is occasionally subjected to a time delay as caused by virtue of the time required to transmit the possibly complicated LF-signal.
Furthermore, a keyless access control device is described in EP 0 767 286 A2. This system employs a mobile HF-transmitter which upon actuation of a transmission button transmits HF-signals to an HF-receiving unit, which is disposed in the motor vehicle, for the purpose of identifying an access authorization and for subsequently opening the vehicle doors. This mobile transmission part is also allocated an LF-transceiver unit which communicates with an LF-transceiver unit disposed in the motor vehicle, if the transmission part which is formed as a key is inserted into a corresponding lock in the motor vehicle, i.e. the ignition lock. The LF-communication serves to perform a predetermined dialogue; furthermore, energy is used over the LF-path for the purpose of charging up a battery which is allocated to the transmission part. Although this access control device is also a keyless access control device, it is still necessary, however, for an authorized user to actively operate the transmission button, in order to gain access to the motor vehicle. The only difference from a conventional way of locking the doors of a motor vehicle is that the transmission button is actuated instead of a lock.
SUMMARY OF THE INVENTION
On the basis of the prior art discussed in the introduction, it is, therefore, the object of the invention to propose a keyless device for controlling access to motor vehicles and to propose a keyless method of checking access authorization in motor vehicles, which device is not only suitable for unlocking individual doors or bonnets and boot lids but which also renders it possible to exchange complicated code and response signals without having to put up with any noticeable delay in
Pretzlaff Volker
Stobbe Anatoli
Brooks & Kushman P.C.
Horabik Michael
Leopold Kostal GmbH & Co.
Shimizu M
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